The Pentagon relies heavily on helicopters, but they’re burdened with limitations.

They’re slow. The large rotor can exceed the speed of sound and bring immense drag. While it’s possible to have rotors that won’t do this, there is no known material from which to make them.

Advancing rotor blades have greater speeds than retreating blades. To avoid an imbalance that would cause major problems, rotors must be able to move. This required “flap” becomes uncontrollable at high speeds and will cause the chopper to stall.

Vibration from the rotors is a huge problem and an awkward monitoring system is often all that keeps a helicopter from shaking itself apart.

Because the rotors require so much power to lift, fuel is burned quickly, while adding more increases the problem. Range is extremely limited.

The military wants its next-generation helicopters to cruise at 195 mph, have a range of 500 miles, and hover at high altitudes in hot weather. Higher, warmer air, is thinner and provides less lift. The Abbottabad heat is what brought down the stealth SEAL chopper during the bin Laden raid.
On top of this, the next-gen choppers will also be expected to fly without pilots, able to integrate various weapons systems, and have open source networking to add “plug-and-play” avionics from a variety of manufacturers.
The Army-led initiative to achieve these goals is called the Joint Multi-Role (JMR) and it expects to have demonstrators flying the skies by 2017. The goal is to have an entirely new fleet of next-generation helicopters by 2030.

Military helicopters have changed little since this Sikorsky R-4 was introduced into the Army Air Corp in 1942

The ultra-class will lift large vehicles like the Stryker, and MRAPs around tomorrow's battlefield

Getting rid of pilots will allow the next-gens to carry more fuel and permit them to operate for more than today's typical two-hour intervals

TODAY: The Sikorsky UH-60L Black Hawk transports troops and equipment to and from active battlefields

Range: Up to 320 miles at 19,000 ftSpeed: Up to 183 mph

The tactical craft, with a $21.3 million pricetag, can be equipped with duel machine-, mini- and Gatling-guns, as well as rockets and laser-guided missiles.

It was the helicopter of choice for the military's recent urban drills over Los Angeles, and U.S. special forces used a highly-modified model in the operation that killed Osama Bin Laden.

TODAY: The MH-6 Little Bird, or 'Killer Egg', is a light attack helicopter most recently used for special operations in Iraq

Range: Up to 230 miles at 18,700 ftSpeed: Up to 175 mph

More agile than the larger Black Hawk, the Little Bird can slip in and out of conflicts at speed. The small helicopter can also pack a relatively large punch with chain- and mini-guns, rockets and air and anti-tank missile systems.

TODAY: The Bell OH-58 Kiowa Warrior's large mounted sight features a thermal imaging system and a laser range finder

Range: Up to 345 miles at 15,000 ftSpeed: Up to 149 mph

Used by the U.S. military since 1969, primarily for armed reconnaissance missions, the Kiowa Warrior has recently faced questions about its age. Itcomes equipped with HELLFIRE and Stinger air-to-air missiles, a .50 calibre machine gun and HYDRA rockets.